1. Field of the Invention
This invention is directed to improved lubricant compositions comprising alkylated thianthrene lubricant fluids alone or in combination with synthetic or mineral oils, and to mineral or synthetic lubricant oil or hydrocarbyl or hydrocarbloxy fuel compositions containing minor amounts of said alkylated thianthrenes as multifunctional additives therefor.
2. Description of Related Art
Polyphenyl sulfides are known and have been used as lubricants/additives in special applications, Polyphenyl sulfides suffer from very high cost due to difficult synthesis and have poor low-temperature properties.
Incorporation of linear alkyl groups into diphenyl sulfide eliminates both of the above problems and provides a novel, relatively inexpensive lubricant having excellent low-temperature properties. The use of these adducts as a lubricant or lubricant additive in either mineral or synthetic lubricants has been recently disclosed as noted in one of the above copending applications.
The principal limitation of getting monoalkylated fluids of diphenyl sulfide using octadecene or lower olefins having greater than 5 cSt viscosity at 100.degree. C. limits end use applications. However, alkylation of thianthrene with hexadecene provides a monoalkylated adduct having a viscosity of &gt;12 cSt. This opens a wider range of application areas for this novel lubricating fluid.
The preparation and use of alkylated thianthrenes as a new class of lubricating fluids is disclosed in the instant application. These fluids have the advantages of alkylated diphenyl sulfides in that the polar sulfur provides excellent additive solubility and good lubricating properties.